Subclasses may be used, for example when the algorithm ID has * associated parameters which some code (e.g. code using public keys) needs * to have parsed. Two examples of such algorithms are Diffie-Hellman key * exchange, and the Digital Signature Standard Algorithm (DSS/DSA). * *
The OID constants defined in this class correspond to some widely
* used algorithms, for which conventional string names have been defined.
* This class is not a general repository for OIDs, or for such string names.
* Note that the mappings between algorithm IDs and algorithm names is
* not one-to-one.
*
*
* @author David Brownell
* @author Amit Kapoor
* @author Hemma Prafullchandra
*/
public class AlgorithmId implements Serializable, DerEncoder {
/** use serialVersionUID from JDK 1.1. for interoperability */
private static final long serialVersionUID = 7205873507486557157L;
/**
* The object identitifer being used for this algorithm.
*/
private ObjectIdentifier algid;
// The (parsed) parameters
private AlgorithmParameters algParams;
private boolean constructedFromDer = true;
/**
* Parameters for this algorithm. These are stored in unparsed
* DER-encoded form; subclasses can be made to automaticaly parse
* them so there is fast access to these parameters.
*/
protected DerValue params;
/**
* Constructs an algorithm ID which will be initialized
* separately, for example by deserialization.
* @deprecated use one of the other constructors.
*/
@Deprecated
public AlgorithmId() { }
/**
* Constructs a parameterless algorithm ID.
*
* @param oid the identifier for the algorithm
*/
public AlgorithmId(ObjectIdentifier oid) {
algid = oid;
}
/**
* Constructs an algorithm ID with algorithm parameters.
*
* @param oid the identifier for the algorithm.
* @param algparams the associated algorithm parameters.
*/
public AlgorithmId(ObjectIdentifier oid, AlgorithmParameters algparams) {
algid = oid;
algParams = algparams;
constructedFromDer = false;
}
private AlgorithmId(ObjectIdentifier oid, DerValue params)
throws IOException {
this.algid = oid;
this.params = params;
if (this.params != null) {
decodeParams();
}
}
protected void decodeParams() throws IOException {
String algidString = algid.toString();
try {
algParams = AlgorithmParameters.getInstance(algidString);
} catch (NoSuchAlgorithmException e) {
/*
* This algorithm parameter type is not supported, so we cannot
* parse the parameters.
*/
algParams = null;
return;
}
// Decode (parse) the parameters
algParams.init(params.toByteArray());
}
/**
* Marshal a DER-encoded "AlgorithmID" sequence on the DER stream.
*/
public final void encode(DerOutputStream out) throws IOException {
derEncode(out);
}
/**
* DER encode this object onto an output stream.
* Implements the DerEncoder interface.
*
* @param out
* the output stream on which to write the DER encoding.
*
* @exception IOException on encoding error.
*/
public void derEncode (OutputStream out) throws IOException {
DerOutputStream bytes = new DerOutputStream();
DerOutputStream tmp = new DerOutputStream();
bytes.putOID(algid);
// Setup params from algParams since no DER encoding is given
if (constructedFromDer == false) {
if (algParams != null) {
params = new DerValue(algParams.getEncoded());
} else {
params = null;
}
}
if (params == null) {
// Changes backed out for compatibility with Solaris
// Several AlgorithmId should omit the whole parameter part when
// it's NULL. They are ---
// rfc3370 2.1: Implementations SHOULD generate SHA-1
// AlgorithmIdentifiers with absent parameters.
// rfc3447 C1: When id-sha1, id-sha224, id-sha256, id-sha384 and
// id-sha512 are used in an AlgorithmIdentifier the parameters
// (which are optional) SHOULD be omitted.
// rfc3279 2.3.2: The id-dsa algorithm syntax includes optional
// domain parameters... When omitted, the parameters component
// MUST be omitted entirely
// rfc3370 3.1: When the id-dsa-with-sha1 algorithm identifier
// is used, the AlgorithmIdentifier parameters field MUST be absent.
/*if (
algid.equals((Object)SHA_oid) ||
algid.equals((Object)SHA224_oid) ||
algid.equals((Object)SHA256_oid) ||
algid.equals((Object)SHA384_oid) ||
algid.equals((Object)SHA512_oid) ||
algid.equals((Object)DSA_oid) ||
algid.equals((Object)sha1WithDSA_oid)) {
; // no parameter part encoded
} else {
bytes.putNull();
}*/
bytes.putNull();
} else {
bytes.putDerValue(params);
}
tmp.write(DerValue.tag_Sequence, bytes);
out.write(tmp.toByteArray());
}
/**
* Returns the DER-encoded X.509 AlgorithmId as a byte array.
*/
public final byte[] encode() throws IOException {
DerOutputStream out = new DerOutputStream();
derEncode(out);
return out.toByteArray();
}
/**
* Returns the ISO OID for this algorithm. This is usually converted
* to a string and used as part of an algorithm name, for example
* "OID.1.3.14.3.2.13" style notation. Use the getName
* call when you do not need to ensure cross-system portability
* of algorithm names, or need a user friendly name.
*/
public final ObjectIdentifier getOID () {
return algid;
}
/**
* Returns a name for the algorithm which may be more intelligible
* to humans than the algorithm's OID, but which won't necessarily
* be comprehensible on other systems. For example, this might
* return a name such as "MD5withRSA" for a signature algorithm on
* some systems. It also returns names like "OID.1.2.3.4", when
* no particular name for the algorithm is known.
*/
public String getName() {
String algName = nameTable.get(algid);
if (algName != null) {
return algName;
}
if ((params != null) && algid.equals((Object)specifiedWithECDSA_oid)) {
try {
AlgorithmId paramsId =
AlgorithmId.parse(new DerValue(getEncodedParams()));
String paramsName = paramsId.getName();
algName = makeSigAlg(paramsName, "EC");
} catch (IOException e) {
// ignore
}
}
return (algName == null) ? algid.toString() : algName;
}
public AlgorithmParameters getParameters() {
return algParams;
}
/**
* Returns the DER encoded parameter, which can then be
* used to initialize java.security.AlgorithmParamters.
*
* @return DER encoded parameters, or null not present.
*/
public byte[] getEncodedParams() throws IOException {
return (params == null) ? null : params.toByteArray();
}
/**
* Returns true iff the argument indicates the same algorithm
* with the same parameters.
*/
public boolean equals(AlgorithmId other) {
boolean paramsEqual =
(params == null ? other.params == null : params.equals(other.params));
return (algid.equals((Object)other.algid) && paramsEqual);
}
/**
* Compares this AlgorithmID to another. If algorithm parameters are
* available, they are compared. Otherwise, just the object IDs
* for the algorithm are compared.
*
* @param other preferably an AlgorithmId, else an ObjectIdentifier
*/
public boolean equals(Object other) {
if (this == other) {
return true;
}
if (other instanceof AlgorithmId) {
return equals((AlgorithmId) other);
} else if (other instanceof ObjectIdentifier) {
return equals((ObjectIdentifier) other);
} else {
return false;
}
}
/**
* Compares two algorithm IDs for equality. Returns true iff
* they are the same algorithm, ignoring algorithm parameters.
*/
public final boolean equals(ObjectIdentifier id) {
return algid.equals((Object)id);
}
/**
* Returns a hashcode for this AlgorithmId.
*
* @return a hashcode for this AlgorithmId.
*/
public int hashCode() {
StringBuilder sbuf = new StringBuilder();
sbuf.append(algid.toString());
sbuf.append(paramsToString());
return sbuf.toString().hashCode();
}
/**
* Provides a human-readable description of the algorithm parameters.
* This may be redefined by subclasses which parse those parameters.
*/
protected String paramsToString() {
if (params == null) {
return "";
} else if (algParams != null) {
return algParams.toString();
} else {
return ", params unparsed";
}
}
/**
* Returns a string describing the algorithm and its parameters.
*/
public String toString() {
return getName() + paramsToString();
}
/**
* Parse (unmarshal) an ID from a DER sequence input value. This form
* parsing might be used when expanding a value which has already been
* partially unmarshaled as a set or sequence member.
*
* @exception IOException on error.
* @param val the input value, which contains the algid and, if
* there are any parameters, those parameters.
* @return an ID for the algorithm. If the system is configured
* appropriately, this may be an instance of a class
* with some kind of special support for this algorithm.
* In that case, you may "narrow" the type of the ID.
*/
public static AlgorithmId parse(DerValue val) throws IOException {
if (val.tag != DerValue.tag_Sequence) {
throw new IOException("algid parse error, not a sequence");
}
/*
* Get the algorithm ID and any parameters.
*/
ObjectIdentifier algid;
DerValue params;
DerInputStream in = val.toDerInputStream();
algid = in.getOID();
if (in.available() == 0) {
params = null;
} else {
params = in.getDerValue();
if (params.tag == DerValue.tag_Null) {
if (params.length() != 0) {
throw new IOException("invalid NULL");
}
params = null;
}
if (in.available() != 0) {
throw new IOException("Invalid AlgorithmIdentifier: extra data");
}
}
return new AlgorithmId(algid, params);
}
/**
* Returns one of the algorithm IDs most commonly associated
* with this algorithm name.
*
* @param algname the name being used
* @deprecated use the short get form of this method.
* @exception NoSuchAlgorithmException on error.
*/
@Deprecated
public static AlgorithmId getAlgorithmId(String algname)
throws NoSuchAlgorithmException {
return get(algname);
}
/**
* Returns one of the algorithm IDs most commonly associated
* with this algorithm name.
*
* @param algname the name being used
* @exception NoSuchAlgorithmException on error.
*/
public static AlgorithmId get(String algname)
throws NoSuchAlgorithmException {
ObjectIdentifier oid;
try {
oid = algOID(algname);
} catch (IOException ioe) {
throw new NoSuchAlgorithmException
("Invalid ObjectIdentifier " + algname);
}
if (oid == null) {
throw new NoSuchAlgorithmException
("unrecognized algorithm name: " + algname);
}
return new AlgorithmId(oid);
}
/**
* Returns one of the algorithm IDs most commonly associated
* with this algorithm parameters.
*
* @param algparams the associated algorithm parameters.
* @exception NoSuchAlgorithmException on error.
*/
public static AlgorithmId get(AlgorithmParameters algparams)
throws NoSuchAlgorithmException {
ObjectIdentifier oid;
String algname = algparams.getAlgorithm();
try {
oid = algOID(algname);
} catch (IOException ioe) {
throw new NoSuchAlgorithmException
("Invalid ObjectIdentifier " + algname);
}
if (oid == null) {
throw new NoSuchAlgorithmException
("unrecognized algorithm name: " + algname);
}
return new AlgorithmId(oid, algparams);
}
/*
* Translates from some common algorithm names to the
* OID with which they're usually associated ... this mapping
* is the reverse of the one below, except in those cases
* where synonyms are supported or where a given algorithm
* is commonly associated with multiple OIDs.
*
* XXX This method needs to be enhanced so that we can also pass the
* scope of the algorithm name to it, e.g., the algorithm name "DSA"
* may have a different OID when used as a "Signature" algorithm than when
* used as a "KeyPairGenerator" algorithm.
*/
private static ObjectIdentifier algOID(String name) throws IOException {
// See if algname is in printable OID ("dot-dot") notation
if (name.indexOf('.') != -1) {
if (name.startsWith("OID.")) {
return new ObjectIdentifier(name.substring("OID.".length()));
} else {
return new ObjectIdentifier(name);
}
}
// Digesting algorithms
if (name.equalsIgnoreCase("MD5")) {
return AlgorithmId.MD5_oid;
}
if (name.equalsIgnoreCase("MD2")) {
return AlgorithmId.MD2_oid;
}
if (name.equalsIgnoreCase("SHA") || name.equalsIgnoreCase("SHA1")
|| name.equalsIgnoreCase("SHA-1")) {
return AlgorithmId.SHA_oid;
}
if (name.equalsIgnoreCase("SHA-256") ||
name.equalsIgnoreCase("SHA256")) {
return AlgorithmId.SHA256_oid;
}
if (name.equalsIgnoreCase("SHA-384") ||
name.equalsIgnoreCase("SHA384")) {
return AlgorithmId.SHA384_oid;
}
if (name.equalsIgnoreCase("SHA-512") ||
name.equalsIgnoreCase("SHA512")) {
return AlgorithmId.SHA512_oid;
}
if (name.equalsIgnoreCase("SHA-224") ||
name.equalsIgnoreCase("SHA224")) {
return AlgorithmId.SHA224_oid;
}
// Various public key algorithms
if (name.equalsIgnoreCase("RSA")) {
return AlgorithmId.RSAEncryption_oid;
}
if (name.equalsIgnoreCase("Diffie-Hellman")
|| name.equalsIgnoreCase("DH")) {
return AlgorithmId.DH_oid;
}
if (name.equalsIgnoreCase("DSA")) {
return AlgorithmId.DSA_oid;
}
if (name.equalsIgnoreCase("EC")) {
return EC_oid;
}
if (name.equalsIgnoreCase("ECDH")) {
return AlgorithmId.ECDH_oid;
}
// Secret key algorithms
if (name.equalsIgnoreCase("AES")) {
return AlgorithmId.AES_oid;
}
// Common signature types
if (name.equalsIgnoreCase("MD5withRSA")
|| name.equalsIgnoreCase("MD5/RSA")) {
return AlgorithmId.md5WithRSAEncryption_oid;
}
if (name.equalsIgnoreCase("MD2withRSA")
|| name.equalsIgnoreCase("MD2/RSA")) {
return AlgorithmId.md2WithRSAEncryption_oid;
}
if (name.equalsIgnoreCase("SHAwithDSA")
|| name.equalsIgnoreCase("SHA1withDSA")
|| name.equalsIgnoreCase("SHA/DSA")
|| name.equalsIgnoreCase("SHA1/DSA")
|| name.equalsIgnoreCase("DSAWithSHA1")
|| name.equalsIgnoreCase("DSS")
|| name.equalsIgnoreCase("SHA-1/DSA")) {
return AlgorithmId.sha1WithDSA_oid;
}
if (name.equalsIgnoreCase("SHA224WithDSA")) {
return AlgorithmId.sha224WithDSA_oid;
}
if (name.equalsIgnoreCase("SHA256WithDSA")) {
return AlgorithmId.sha256WithDSA_oid;
}
if (name.equalsIgnoreCase("SHA1WithRSA")
|| name.equalsIgnoreCase("SHA1/RSA")) {
return AlgorithmId.sha1WithRSAEncryption_oid;
}
if (name.equalsIgnoreCase("SHA1withECDSA")
|| name.equalsIgnoreCase("ECDSA")) {
return AlgorithmId.sha1WithECDSA_oid;
}
if (name.equalsIgnoreCase("SHA224withECDSA")) {
return AlgorithmId.sha224WithECDSA_oid;
}
if (name.equalsIgnoreCase("SHA256withECDSA")) {
return AlgorithmId.sha256WithECDSA_oid;
}
if (name.equalsIgnoreCase("SHA384withECDSA")) {
return AlgorithmId.sha384WithECDSA_oid;
}
if (name.equalsIgnoreCase("SHA512withECDSA")) {
return AlgorithmId.sha512WithECDSA_oid;
}
// See if any of the installed providers supply a mapping from
// the given algorithm name to an OID string
String oidString;
if (!initOidTable) {
Provider[] provs = Security.getProviders();
for (int i=0; i